11815621 has 2 divisors, whose sum is σ = 11815622. Its totient is φ = 11815620.

The previous prime is 11815613. The next prime is 11815627. The reversal of 11815621 is 12651811.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7214596 + 4601025 = 2686^2 + 2145^2 .

It is a cyclic number.

It is not a de Polignac number, because 11815621 - 2³ = 11815613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11815627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5907810 + 5907811.

It is an arithmetic number, because the mean of its divisors is an integer number (5907811).

Almost surely, 2^11815621 is an apocalyptic number.

It is an amenable number.

11815621 is a deficient number, since it is larger than the sum of its proper divisors (1).

11815621 is an equidigital number, since it uses as much as digits as its factorization.

11815621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 480, while the sum is 25.

The square root of 11815621 is about 3437.3857799205. The cubic root of 11815621 is about 227.7642286783.

The spelling of 11815621 in words is "eleven million, eight hundred fifteen thousand, six hundred twenty-one".